Christine,
How odd would it look for a girl that is 6' to be wearing 4" heels dear? I have a pair of black slipon cork sole four in heals that I baught this past june to wear during the Be All and believe me when I say I was not the only tall girl there wearing heals that high.
It all depends on what you are comfortable with. I don't worry about what people around me think as long as the shoe is comfortable and I can walk in it. Just remember that the higher the heal the more your calfs will ache until you get use to walking in them.
Anna